Dihydropyrimidinase protects from DNA replication stress caused by cytotoxic metabolites.

Imbalance in the level of the pyrimidine degradation products dihydrouracil and dihydrothymine is associated with cellular transformation and cancer progression. Dihydropyrimidines are degraded by dihydropyrimidinase (DHP), a zinc metalloenzyme that is upregulated in solid tumors but not in the corresponding normal tissues. How dihydropyrimidine metabolites affect cellular phenotypes remains elusive. Here we show that the suppression of DHP in cancer cell lines is cytotoxic. An increase in the level of dihydropyrimidines induced DNA replication and transcriptional stress. Cells lacking DHP accumulated DNA-protein crosslinks (DPCs), including covalently trapped DNA polymerase eta. Furthermore, we show that the plant flavonoid dihydromyricetin inhibits human DHP activity. Cellular exposure to dihydromyricetin triggered DPCs-dependent DNA replication stress in cancer cells. This study defines dihydropyrimidines as potentially cytotoxic metabolites that may offer an opportunity for therapeutic-targeting of DHP activity in solid tumors.

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Dihydropyrimidinase protects from DNA replication stress caused by cytotoxic metabolites

Nucleic Acids Research ◽

10.1093/nar/gkz1162 ◽

2019 ◽

Vol 48 (4) ◽

pp. 1886-1904 ◽

Cited By ~ 1

Author(s):

Jihane Basbous ◽

Antoine Aze ◽

Laurent Chaloin ◽

Rana Lebdy ◽

Dana Hodroj ◽

...

Keyword(s):

Dna Replication ◽

Solid Tumors ◽

Cancer Progression ◽

Degradation Products ◽

Replication Stress ◽

Cellular Transformation ◽

Chromosomal Dna ◽

Normal Tissues ◽

Dna Replication Stress ◽

Pyrimidine Degradation

Abstract Imbalance in the level of the pyrimidine degradation products dihydrouracil and dihydrothymine is associated with cellular transformation and cancer progression. Dihydropyrimidines are degraded by dihydropyrimidinase (DHP), a zinc metalloenzyme that is upregulated in solid tumors but not in the corresponding normal tissues. How dihydropyrimidine metabolites affect cellular phenotypes remains elusive. Here we show that the accumulation of dihydropyrimidines induces the formation of DNA–protein crosslinks (DPCs) and causes DNA replication and transcriptional stress. We used Xenopus egg extracts to recapitulate DNA replication invitro. We found that dihydropyrimidines interfere directly with the replication of both plasmid and chromosomal DNA. Furthermore, we show that the plant flavonoid dihydromyricetin inhibits human DHP activity. Cellular exposure to dihydromyricetin triggered DPCs-dependent DNA replication stress in cancer cells. This study defines dihydropyrimidines as potentially cytotoxic metabolites that may offer an opportunity for therapeutic-targeting of DHP activity in solid tumors.

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Interferon alpha-inducible protein 6 regulates NRASQ61K-induced melanomagenesis and growth

eLife ◽

10.7554/elife.16432 ◽

2016 ◽

Vol 5 ◽

Cited By ~ 3

Author(s):

Romi Gupta ◽

Matteo Forloni ◽

Malik Bisserier ◽

Shaillay Kumar Dogra ◽

Qiaohong Yang ◽

...

Keyword(s):

Dna Replication ◽

Interferon Alpha ◽

Replication Stress ◽

Cellular Transformation ◽

Mek Inhibitor ◽

Cytotoxic Effects ◽

Dna Replication Stress ◽

Increased Sensitivity ◽

Inducible Protein ◽

Melanoma Growth

Mutations in the NRAS oncogene are present in up to 20% of melanoma. Here, we show that interferon alpha-inducible protein 6 (IFI6) is necessary for NRASQ61K-induced transformation and melanoma growth. IFI6 was transcriptionally upregulated by NRASQ61K, and knockdown of IFI6 resulted in DNA replication stress due to dysregulated DNA replication via E2F2. This stress consequentially inhibited cellular transformation and melanoma growth via senescence or apoptosis induction depending on the RB and p53 pathway status of the cells. NRAS-mutant melanoma were significantly more resistant to the cytotoxic effects of DNA replication stress-inducing drugs, and knockdown of IFI6 increased sensitivity to these drugs. Pharmacological inhibition of IFI6 expression by the MEK inhibitor trametinib, when combined with DNA replication stress-inducing drugs, blocked NRAS-mutant melanoma growth. Collectively, we demonstrate that IFI6, via E2F2 regulates DNA replication and melanoma development and growth, and this pathway can be pharmacologically targeted to inhibit NRAS-mutant melanoma.

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LIM Protein Ajuba associates with the RPA complex through direct and cell cycle-dependent interaction with the RPA70 subunit

10.1101/177840 ◽

2017 ◽

Author(s):

Sandy Fowler ◽

Pascal Maguin ◽

Sampada Kalan ◽

Diego Loayza

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Genome Stability ◽

Replication Stress ◽

Cellular Transformation ◽

Early Event ◽

Lim Protein ◽

Show Evidence ◽

Dna Replication Stress ◽

Cycle Dependent

AbstractDNA damage response pathways are essential for genome stability and cell survival. Specifically, the ATR kinase is activated by DNA replication stress. An early event in this activation is the recruitment and phosphorylation of RPA, a single stranded DNA binding complex composed of three subunits, RPA70,RPA32 and RPA14. We have previously shown that the LIM protein Ajuba associates with RPA, and that depletion of Ajuba leads to potent activation of ATR. In this study, we show evidence that the Ajuba-RPA interaction occurs through direct protein contact with RPA70, and that their association is cell cycle-regulated and is reduced upon DNA replication stress. We propose a model in which Ajuba negatively regulates the ATR pathway by directly interacting with RPA70, thereby preventing an inappropriate ATR activation. Our results provide a framework to understand the mechanism of regulation of ATR in human cells, which is important to prevent cellular transformation and tumorigenesis.

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Faculty Opinions recommendation of Mitochondrial hyperfusion induced by loss of the fission protein Drp1 causes ATM-dependent G2/M arrest and aneuploidy through DNA replication stress.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717982066.793472722 ◽

2013 ◽

Author(s):

Timothy Yen

Keyword(s):

Dna Replication ◽

Replication Stress ◽

Dna Replication Stress

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Faculty Opinions recommendation of Cdc45 is a critical effector of myc-dependent DNA replication stress.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718007686.793476146 ◽

2013 ◽

Author(s):

David Cortez

Keyword(s):

Dna Replication ◽

Replication Stress ◽

Dna Replication Stress

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Faculty Opinions recommendation of Intragenic origins due to short G1 phases underlie oncogene-induced DNA replication stress.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.732721887.793543555 ◽

2018 ◽

Author(s):

Olivier Hyrien

Keyword(s):

Dna Replication ◽

Replication Stress ◽

Dna Replication Stress

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Targeting DNA Replication Stress for Cancer Therapy

Genes ◽

10.3390/genes7080051 ◽

2016 ◽

Vol 7 (8) ◽

pp. 51 ◽

Cited By ~ 36

Author(s):

Jun Zhang ◽

Qun Dai ◽

Dongkyoo Park ◽

Xingming Deng

Keyword(s):

Dna Replication ◽

Cancer Therapy ◽

Replication Stress ◽

Dna Replication Stress

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Targeting the DNA replication stress phenotype of KRAS mutant cancer cells

Scientific Reports ◽

10.1038/s41598-021-83142-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tara Al Zubaidi ◽

O. H. Fiete Gehrisch ◽

Marie-Michelle Genois ◽

Qi Liu ◽

Shan Lu ◽

...

Keyword(s):

Dna Replication ◽

Single Molecule ◽

Replication Stress ◽

Proton Radiation ◽

Wild Type ◽

Cellular Effects ◽

Proton Treatment ◽

Dna Replication Stress ◽

Fork Stalling ◽

Mutant Cells

AbstractMutant KRAS is a common tumor driver and frequently confers resistance to anti-cancer treatments such as radiation. DNA replication stress in these tumors may constitute a therapeutic liability but is poorly understood. Here, using single-molecule DNA fiber analysis, we first characterized baseline replication stress in a panel of unperturbed isogenic and non-isogenic cancer cell lines. Correlating with the observed enhanced replication stress we found increased levels of cytosolic double-stranded DNA in KRAS mutant compared to wild-type cells. Yet, despite this phenotype replication stress-inducing agents failed to selectively impact KRAS mutant cells, which were protected by CHK1. Similarly, most exogenous stressors studied did not differentially augment cytosolic DNA accumulation in KRAS mutant compared to wild-type cells. However, we found that proton radiation was able to slow fork progression and preferentially induce fork stalling in KRAS mutant cells. Proton treatment also partly reversed the radioresistance associated with mutant KRAS. The cellular effects of protons in the presence of KRAS mutation clearly contrasted that of other drugs affecting replication, highlighting the unique nature of the underlying DNA damage caused by protons. Taken together, our findings provide insight into the replication stress response associated with mutated KRAS, which may ultimately yield novel therapeutic opportunities.

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